title: Thiols stabilize cobblestone morphology of cultured mesothelial cells.
abstract: Cellular thiols including GSH (glutathione) and L-Cys (L-cysteine) are essential for cell signalling, growth and differentiation. L-Cys is derived from the extracellular thiol pool and is the rate-limiting compound for intracellular GSH biosynthesis. The present study investigated the effect of thiol-supplemented medium on cell growth, phenotype and total GSH of cultured hPMCs (human peritoneal mesothelial cells). Cells were cultured in medium M199 supplemented with 2% serum, with 'plus' or without 'minus' L-Cys and compared with medium supplemented with either β-ME (β-mercaptoethanol) (0.25 mmol/l) or the receptor tyrosine kinase ligand EGF (epidermal growth factor, 100 ng/ml). β-ME produced a disproportionate increase in total GSH compared with L-Cys and other thiols tested [(procysteine (2-oxothiazolidine-4-carboxylic acid) or NAC (N-acetyl-L-cysteine)], while growth and morphology were identical. Cell behaviour of primary hPMCs is characterized by the transition of fibroblastoid to cobblestone morphology during early passage. L-Cys and β-ME promoted a rapid MET (mesenchymal-to-epithelial transition) within 3 days of culture, confirmed by the presence of cobblestone cells, intact organelles, abundant microvilli, primary cilia and cortical actin. In contrast, EGF produced a biphasic response consisting of delayed growth and retention of a fibroblastoid morphology. During a rapid log phase of growth, MET was accompanied by rapid catch-up growth. Thiols may stabilize the epithelial phenotype by engaging redox-sensitive receptors and transcription factors that modulate differentiation. These data may benefit researchers working on thiol-mediated cell differentiation and strategies to regenerate damage to serosal membranes.
authors.affiliation: Department of Medical and Surgical Sciences, University of Otago, Dunedin School of Medicine, Dunedin, New Zealand.
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Bird
authors.forename: Michael
authors.initials: M
authors.lastname: Legge
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Walker
mesh_terms: D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation; D048430:Cell Shape / Q000187:drug effects; D002478:Cells, Cultured; D003545:Cysteine / Q000494:pharmacology*; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D004847:Epithelial Cells / Q000166:cytology* / Q000187:drug effects*; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects; D004848:Epithelium / Q000187:drug effects; D005978:Glutathione / Q000096:biosynthesis*; D006801:Humans; D008623:Mercaptoethanol / Q000494:pharmacology*; D008854:Microscopy, Electron; D008858:Microscopy, Phase-Contrast; D018384:Oxidative Stress; D010537:Peritoneum / Q000166:cytology / Q000187:drug effects; D010641:Phenotype; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction; D013438:Sulfhydryl Compounds / Q000494:pharmacology*
chemical_list: D017382:Reactive Oxygen Species; D013438:Sulfhydryl Compounds; D008623:Mercaptoethanol; D004815:Epidermal Growth Factor; D005978:Glutathione; D003545:Cysteine